Objective To investigate the prevalence rate of non-alcoholic fatty liver disease (NAFLD) in overweight/obese children who visit a hospital, and to explore the influencing factors of NAFLD, in order to provide a basis for the prevention of NAFLD in overweight/obese children. Methods Overweight/obese children who visited Hunan Children's Hospital from June 2019 to September 2021 were recruited. The prevalence rate of NAFLD was examined. Logistic regression analysis was used to explore the factors influencing the development of NAFLD [non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH)]. Receiver operating characteristic curve analysis was used to evaluate the predictive value of the influencing factors for NAFL and NASH. Results A total of 844 overweight/obese children aged 6-17 years were enrolled. The prevalence rate of NAFLD in overweight/obese children was 38.2% (322/844), among which the prevalence rates of NAFL and NASH were 28.8% (243/844) and 9.4% (79/844), respectively. Multivariate logistic regression analysis showed that the increase of waist-to-hip ratio (WHR) and low high-density lipoprotein cholesterol (HDL-C) were associated with the development of NAFL and NASH (P<0.05). The receiver operating characteristic curve analysis showed that the combined measurement of WHR and HDL-C had a predictive value for NAFL (area under the curve: 0.653, 95%CI: 0.613-0.694), and for NASH (area under the curve: 0.771, 95%CI: 0.723-0.819). Conclusions The prevalence rate of NAFLD in overweight/obese children who visit a hospital is high. WHR and HDL-C are associated with the development of NAFLD and the combined measurement of WHR and HDL-C has a certain value for predicating the development of NAFLD.